diff --git a/src/Symfony/Component/ObjectMapper/Exception/NoSuchPropertyException.php b/src/Symfony/Component/ObjectMapper/Exception/NoSuchPropertyException.php
new file mode 100644
index 0000000000000..3b5df303dcc1f
--- /dev/null
+++ b/src/Symfony/Component/ObjectMapper/Exception/NoSuchPropertyException.php
@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ObjectMapper\Exception;
+
+/**
+ * Thrown when a property cannot be found.
+ *
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ */
+class NoSuchPropertyException extends MappingException
+{
+}
diff --git a/src/Symfony/Component/ObjectMapper/ObjectMapper.php b/src/Symfony/Component/ObjectMapper/ObjectMapper.php
index 69f02fb7f1160..dc493c0e6a4c8 100644
--- a/src/Symfony/Component/ObjectMapper/ObjectMapper.php
+++ b/src/Symfony/Component/ObjectMapper/ObjectMapper.php
@@ -14,6 +14,7 @@
 use Psr\Container\ContainerInterface;
 use Symfony\Component\ObjectMapper\Exception\MappingException;
 use Symfony\Component\ObjectMapper\Exception\MappingTransformException;
+use Symfony\Component\ObjectMapper\Exception\NoSuchPropertyException;
 use Symfony\Component\ObjectMapper\Metadata\Mapping;
 use Symfony\Component\ObjectMapper\Metadata\ObjectMapperMetadataFactoryInterface;
 use Symfony\Component\ObjectMapper\Metadata\ReflectionObjectMapperMetadataFactory;
@@ -167,7 +168,15 @@ public function map(object $source, object|string|null $target = null): object
 
     private function getRawValue(object $source, string $propertyName): mixed
     {
-        return $this->propertyAccessor ? $this->propertyAccessor->getValue($source, $propertyName) : $source->{$propertyName};
+        if ($this->propertyAccessor) {
+            return $this->propertyAccessor->getValue($source, $propertyName);
+        }
+
+        if (!property_exists($source, $propertyName) && !(method_exists($source, '__isset') && true === $source->__isset($propertyName))) {
+            throw new NoSuchPropertyException(sprintf('The property "%s" does not exist on "%s".', $propertyName, get_debug_type($source)));
+        }
+
+        return $source->{$propertyName};
     }
 
     private function getSourceValue(object $source, object $target, mixed $value, \SplObjectStorage $objectMap, ?Mapping $mapping = null): mixed
diff --git a/src/Symfony/Component/ObjectMapper/Tests/Fixtures/DefaultValueStdClass/TargetDto.php b/src/Symfony/Component/ObjectMapper/Tests/Fixtures/DefaultValueStdClass/TargetDto.php
new file mode 100644
index 0000000000000..d4aa289184d50
--- /dev/null
+++ b/src/Symfony/Component/ObjectMapper/Tests/Fixtures/DefaultValueStdClass/TargetDto.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Symfony\Component\ObjectMapper\Tests\Fixtures\DefaultValueStdClass;
+
+use Symfony\Component\ObjectMapper\Attribute\Map;
+
+class TargetDto
+{
+    public function __construct(
+        public string  $id,
+        #[Map(source: 'optional', if: [self::class, 'isDefined'])]
+        public ?string $optional = null,
+    )
+    {
+    }
+
+    public static function isDefined($source): bool {
+        return isset($source);
+    }
+}
diff --git a/src/Symfony/Component/ObjectMapper/Tests/ObjectMapperTest.php b/src/Symfony/Component/ObjectMapper/Tests/ObjectMapperTest.php
index 99153c3fbdfc7..9e0a61104420b 100644
--- a/src/Symfony/Component/ObjectMapper/Tests/ObjectMapperTest.php
+++ b/src/Symfony/Component/ObjectMapper/Tests/ObjectMapperTest.php
@@ -15,6 +15,7 @@
 use Psr\Container\ContainerInterface;
 use Symfony\Component\ObjectMapper\Exception\MappingException;
 use Symfony\Component\ObjectMapper\Exception\MappingTransformException;
+use Symfony\Component\ObjectMapper\Exception\NoSuchPropertyException;
 use Symfony\Component\ObjectMapper\Metadata\Mapping;
 use Symfony\Component\ObjectMapper\Metadata\ObjectMapperMetadataFactoryInterface;
 use Symfony\Component\ObjectMapper\Metadata\ReflectionObjectMapperMetadataFactory;
@@ -28,6 +29,7 @@
 use Symfony\Component\ObjectMapper\Tests\Fixtures\DeeperRecursion\RecursiveDto;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\DeeperRecursion\Relation;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\DeeperRecursion\RelationDto;
+use Symfony\Component\ObjectMapper\Tests\Fixtures\DefaultValueStdClass\TargetDto;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\Flatten\TargetUser;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\Flatten\User;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\Flatten\UserProfile;
@@ -236,8 +238,16 @@ public function testSourceOnly()
         $mapped = $mapper->map($a, SourceOnly::class);
         $this->assertInstanceOf(SourceOnly::class, $mapped);
         $this->assertSame('test', $mapped->mappedName);
+    }
 
+    public function testSourceOnlyWithMagicMethods()
+    {
+        $mapper = new ObjectMapper();
         $a = new class {
+            public function __isset(string $key): bool {
+                return $key === 'name';
+            }
+
             public function __get(string $key): string
             {
                 return match ($key) {
@@ -303,4 +313,27 @@ public function testMultipleTargetMapProperty()
         $this->assertEquals('donotmap', $c->foo);
         $this->assertEquals('foo', $c->doesNotExistInTargetB);
     }
+
+    public function testDefaultValueStdClass()
+    {
+        $this->expectException(NoSuchPropertyException::class);
+        $u = new \stdClass();
+        $u->id = 'abc';
+        $mapper = new ObjectMapper();
+        $b = $mapper->map($u, TargetDto::class);
+        $this->assertInstanceOf(TargetDto::class, $b);
+        $this->assertEquals('abc', $b->id);
+        $this->assertEquals(null, $b->optional);
+    }
+
+    public function testDefaultValueStdClassWithPropertyInfo()
+    {
+        $u = new \stdClass();
+        $u->id = 'abc';
+        $mapper = new ObjectMapper(propertyAccessor: PropertyAccess::createPropertyAccessorBuilder()->disableExceptionOnInvalidPropertyPath()->getPropertyAccessor());
+        $b = $mapper->map($u, TargetDto::class);
+        $this->assertInstanceOf(TargetDto::class, $b);
+        $this->assertEquals('abc', $b->id);
+        $this->assertEquals(null, $b->optional);
+    }
 }